Renesas Introduces SiGe Power Transistor for 2.4/5GHz Wireless LAN Routers, RF Tag Readers/Writers

Renesas Technology America, Inc. announced the RQG2003 high-performance power SiGe HBT, a device that achieves a level of performance at 2.4GHz and 5GHz. In IEEE 802.11 a/b/g wireless LAN routers/terminals, RF (radio frequency) tag readers/writers, digital cordless phones, and similar products, the company claims that this power transistor can eliminate the power amplifier modules and MMICs (Monolithic Microwave Integrated Circuits) typically used to drive the transmitting antenna. As a result, it allows engineers to design systems that consume less power, are smaller, and cost less to build.

Performance of the RQG2003 power transistor is unmatched. At 5.8GHz, for example, the SiGe device has a power gain of 6.4 dB, a 1-dB gain compression power of 26.5 dBm, and a power addition efficiency of 33.6%. At 2.4GHz, it provides a power gain of 13.0 dB, a 1-dB gain compression power of 26.5 dBm, and a power addition efficiency of 66.0%. Compared with the previous-generation Renesas solution, the HSG2002 transistor, the new RQG2003 device improves addition efficiency by approximately 10 percent at 5.8GHz and by about 20% at 2.4GHz, consuming less power to achieve the required output signal level in both bands.

The RQG2003 is the first Renesas Technology product to use the company’s double-trench structure, in which trench isolation and a conductive trench are formed in a single transistor area. This structure reduces the parasitic capacitance between the substrate and transistor that degrades high-frequency characteristics, resulting in a major improvement in power gain and power addition efficiency in the 2.4GHz and 5GHz bands. Also, the conductive trench is constructed in a way that connects the electrodes and substrate by means of via holes, making it possible to reduce the inductance originating from wire bonding, for improvement in power gain and power addition efficiency.

The RF power transistor is built with a SiGeC process, in which a SiGe base is doped with carbon, and has an optimized transistor pattern. These techniques have increased the collector current density and improved the 1-dB gain compression power by approximately 1.5 dBm compared with the HSG2002 device. The RQG2003 uses an optimal silver paste to achieve high reliability and conductivity for die bonding. A Sn-Bi (stannum-bismuth) compound is used for package electrode plating, providing a totally lead-free implementation. Unlike other non SiGe-based high-frequency power transistors, the Renesas RQG2003 is an eco-friendly product.

To provide an extensive range of products to meet evolving market needs, Renesas Technology plans to further extend the LNA (low noise amplifier) RQG1xxx and PA (power amplifier) RQG2xxx lineups in the RQG Series of SiGe transistors. The company is also developing LNA RQL1xxx and PA RQL2xxx products in the RQL Series of SiGe MMICs.